Internal combustion engines may be used to provide motive power to a vehicle. Cooling may be provided to internal combustion engines, in principle, in the form of air cooling systems or liquid cooling systems. However, the addition or integration of various components into the engine may increase thermal loading on the engine. Specifically, it may be desirable to increase the compactness of the engine to decrease vehicle size and/or increase internal space in the vehicle via the integration of certain parts into others, such as the integration of the exhaust manifold into the cylinder head and/or cylinder block. This may in turn lead to increased thermal loading on the engine beyond acceptable levels. Therefore, it may be desirable to utilize liquid cooling systems as opposed to air cooling systems to remove heat from the engine due to the greater quantity of heat that may be removed via liquid cooling systems when compared to air cooling systems.
Liquid cooling systems may include at least one cooling jacket having cooling channels traversing a cylinder head. The coolant in the liquid cooling system may include water mixed with additives. The liquid cooling system may also include a pump for circulating coolant through the cooling jacket. The heat delivered to the coolant in the cooling jacket may be discharged from the cylinder head via discharge lines, which may be in fluidic communication with a heat exchanger.
To reduce the fuel consumption, rapid heating of the engine oil is expedient for the purpose of reducing friction in lubricated components, in particular after a cold start. Heating the engine oil reduces the viscosity of the oil and thus reduces friction in the lubricated components, in particular in bearings supplied with oil, such as crankshaft bearings.
Therefore, in some prior art engines oil is actively heated, for example, by an external heating device. Alternatively, the engine oil which has been heated during engine operation may be stored in an insulated tank, so that during start-up, oil which has been already heated is ready for use. Alternatively, a coolant-operated oil cooler may be diverted from its intended purpose in the warm-up phase and utilized for heating the oil. This, however, requires coolant which has already been heated. The engine oil may be heated in an accelerated manner via decreasing the amount of heat removed from the coolant in the cooling system during a warm-up phase.
To adjust the liquid cooling system automatically controlled temperature-dependent valves have been used. Specifically, the automatically controlled temperature-dependent valves may be used to decrease (e.g., inhibit) coolant flow during warm-up to increase the rate of heating of the engine. The automatically controlled valves are commonly thermostats that comprise a temperature-reactive element subjected to coolant in the cooling system. The automatically controlled valves are positioned at an inlet of the cooling jacket or upstream of the inlet in a supply line and may open or close based on the temperature of the coolant.
In some examples, the temperature-dependent valve may be positioned so that the coolant bypasses a heat exchanger when the valve is closed. In other examples, the temperature-dependent valve may be positioned in a supply line so that coolant flow through the cooling jacket is inhibited when the valve is closed. Opening the valve may enable coolant to flow through the heat exchanger and/or cooling jacket. In this way, the temperature of the engine may be adjusted by the temperature dependent valve. It will be appreciated that coolant flows through the valve even when it is closed to subject the temperature-reactive element to the coolant. It will be appreciated that when coolant flow is inhibited in the cooling jacket, the engine temperature increases more rapidly during warm-up. Specifically, the temperature-dependent valve is opened when the coolant temperature exceeds a specific threshold temperature. Likewise, the temperature-dependent valve is closed when the coolant temperature falls below the threshold temperature. Generally, the thermostat opens and closes repeatedly during the warm-up phase. Such a control would additionally promote the heating of the engine oil and further reduce the friction in lubricated components. In some examples, the temperature-dependent valve may be configured to flow coolant into a compensation tank when closed to inhibit coolant flow through the cooling jacket. Coolant valves of the aforementioned type are controlled by engine control systems which may include memory executable by a processor.
The German published patent application DE 10 2004 058 864 A1 discloses electronically controlled valves which may be arranged in connection with a cooling system. In addition to simple opening/closing valves with a vacuum cell or with a magnet as an actuator, a valve is disclosed which uses a redundant safeguard system. In this case, an electromagnet is actuated by the engine control system and, when current flows through a valve plate, lifts, i.e. opens, against a spring force, wherein a sufficiently high vacuum prevailing at high engine speeds also moves said plate. Additionally, a safety expansion element opens the valve, when a limit temperature is reached, in turn by lifting the valve plate.
The Inventors have recognized several drawbacks with the aforementioned cooling system. Firstly, the high cost of electrically controlled and actuated valves increase the cost of the engine. As a result, it may not be desirable to use the electrically controlled valves in mass produced engines where cost is a concern. Another drawback of the electrically controlled valve is the complexity of the control system and valve. Specifically, the electromagnet in the valve may fail and/or malfunction. As a result, thermal overloading of the internal combustion engine may occur, thereby degrading engine operation.
As such in one approach, an internal combustion engine is provided. The internal combustion engine includes an oil circuit and a pump in fluidic communication with a supply line and at least one lubricant receiving component and a liquid cooling system including a coolant circuit having an oil pressure actuated coolant valve and a coolant valve control line in fluidic communication with the pump and having a first configuration in which coolant may flow therethrough and a second configuration in which coolant is inhibited from flowing therethrough, the first and second configurations triggered in response to a change in oil pressure in the coolant valve control line.
In this way, the valve may be passively adjusted to alter the coolant flow in the liquid cooling system passively in response to changes in oil pressure. It will be appreciated that the cost of the oil pressure actuated coolant valve may be lower than electronically controlled valves due to the decreased complexity of the oil pressure actuated coolant valve. Moreover, the oil pressure actuated coolant valve may be more robust than electronically controlled valves due to the decreased complexity.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
The invention is described in more detail hereinafter with reference to FIGS. 1-5.